WS bootstrap: Default CCA threshold to -60dBm (#2377)

Author: Jarkko Paso

source/6LoWPAN/ws/ws_common_defines.h

@@ -322,7 +322,7 @@ typedef struct ws_bs_ie {
 /*
  * Automatic CCA threshold: default threshold and range in dBm.
  */
-#define CCA_DEFAULT_DBM -85
+#define CCA_DEFAULT_DBM -60
 #define CCA_HIGH_LIMIT  -60
 #define CCA_LOW_LIMIT   -100